"The discussion of the emplacement and origin of granites should not be generalized to consider all rocks of the granite- granodiorite family, but a distinction should first be made between different members of this family. Particularly the role of potash feldspar, and especially the kind, must be considered; the conditions of formation of microcline, the prevalent potash feldspar in Precambrian granites, are as yet obscure but definitely limit the possibilities of the origin of potassic rocks . . . . Only the emplacement of late-kinematic (and post-kinematic) granites is considered to involve actual problems of the emplacement of granites. For most synkinematic 'granites,' the metasomatic origin is obvious, and they are frequently poor in potassium; their 'emplacement' is hardly a problem. The synkinematic granites with much potassium are generally porphyroblastic, and their microcline has been mainly concentrated into the insets. Such granites form a separate problem."